The display of time related magnitudes, such as the date, moon phase, tides, day and month, is generally achieved in mechanical timepieces by using wheel sets driven by the movement, most often by the hour wheel. Certain of these relative magnitudes require corrections by making up time, either, in the case of a date, to make up for leap years, or in the case of moon phases, to compensate for the slight difference between the lunar months and the approximation made thereof by the gear train. These corrections may also prove necessary if references are lost, for example after the timepiece suffers a shock.
Conventionally, this type of display includes a disc or a ring, respectively integral with a toothed wheel or a toothed crown, or suchlike, and the timepiece movement drives said wheel or said crown at a certain rate at the required frequency.
For a long time, displays of this type have been corrected by using an additional push button, which acts directly on the toothing, as in U.S. Pat. No. 508,467 in the name of CLARK, wherein this push button is formed by a bent spring, which abuts against one tooth of the toothing, retained by a jumper spring, and each abutment on the bent spring causes the toothing to pivot forward by one tooth.
Similarly, CH Patent No 671 317 in the name of GAGNEBIN discloses a push button acting on a pivoting adjustment lever, which acts against a spring, and wherein one tooth of the lever directly meshes with the moon phase wheel, which cooperates with a jumper spring.
A similar arrangement is seen in CH Patent No 4542 in the name of ABEGGLEN, wherein a first push button pivots and cooperates with a lunar wheel in a direct tooth driving arrangement. A second pivoting push button pivots a star-wheel, which is retained by a jumper spring, and cooperates with a tooth, formed by a spring comprised in a first date change wheel, in order to pivot said first date change wheel and to drive an intermediate wheel, which in turn drives a second date change wheel including a spring, which returns a pivoting, peripheral, lifting piece having the function of a click, which in turn drives a date wheel.
However, the drawback of these simple devices is that there is a risk of a sealing defect at the location of the push button used for correcting the display.
Thus, it has been envisaged to perform correction of the display by using pre-existing adjustment means found in the timepiece, in this instance the winding and time-setting stem in the case of a watch.
Thus, CH Patent No 672 223 in the name of CATENA discloses a tide and moon phase indicator, via action of the stem, in the time-setting position, in the negative direction. The mechanism includes two toothed wheels: a top wheel driven onto the hour wheel and another bottom wheel, friction mounted thereon. Each wheel drives a ring: a top ring superposed on a bottom ring, and the gear ratios in each pair comprising a toothed wheel and ring are different, so that the bottom ring rotates more slowly than the top ring, by disconnecting a friction connection on the hour wheel. Apertures on the top ring, and a suitable combination of gear ratios, allow the moon phases to be displayed in a sector of the bottom ring delimited by the top ring. The top ring always follows the hour hand, the bottom ring is retained by a click when the hour wheel is rotating in the negative direction, and it is then possible to correct the moon phase by rotating the top ring alone.
EP Patent No 0 107 177, in the name of ERARD, also discloses a moon phase display mechanism, with synchronisation via the time-setting mechanism and adjustment by turning back on the motion work. In a similar manner, the hour wheel carries a moon pinion driving an intermediate wheel which drives a moon wheel. This moon pinion itself carries a moon phase pinion, free to move and friction mounted via an annular friction spring, and said moon phase pinion drives an intermediate wheel, which drives a moon phase wheel coaxial to the moon wheel. The moon phase pinion cooperates with a click, which only allows the moon phase pinion to pivot if the hour wheel is pivoted clockwise, and otherwise blocks said wheel, which allows the moon phase to be corrected.
CH Patent 577 197, in the name of EBAUCHES SA, discloses mechanism for correcting the date via a moveable selector, controlled by the control stem via the pull out piece. This moveable selector cooperates, in some of its positions with a pivoting lever, one arm of which cooperates with the groove of the sliding pinion. This pivoting lever carries a wheel, which, when the control stem is pushed in, is arranged to cooperate with the motion work in a first lever stop position, and a star-wheel arranged to mesh with a date crown in a second lever stop position. The wheel and star-wheel are coaxial to each other. When the control stem is pulled out, this pivoting lever may also occupy an intermediate position, where the star-wheel is released from the crown and where the wheel is released from the motion work but cooperates with the beak of the pivoting selector, in a first selection position, corresponding to a pivoting movement of the stem in the clockwise direction, and in a second selection position corresponding to a pivoting movement of the stem in the anti-clockwise direction. A preferred embodiment, which combines the time-setting, calendar correction and winding functions, involves an intermediate lever, pivotally mounted on the plate, which carries the crown wheel, and which cooperates at the end of an arm comprised therein, with the pull-out piece and/or the moveable selector, which has a pin capable of being abutted against the pivoting lever carrying the wheel and the star-wheel. When the stem is in the pushed-in position, and is pivoting in the clockwise direction, the crown wheel drives the additional lever in cooperation with the moveable selector in a position where the selector has no action on the pivoting lever, which is in its intermediate position, and where the crown wheel can mesh with a barrel ratchet to wind said ratchet. When the stem pivots in the anti-clockwise direction, the crown wheel is unmeshed from the barrel ratchet and the selector is in a selection position. When the stem is pulled out from the winding position, the intermediate lever and the moveable selector occupy a position where the selector pin pushes the pivoting lever towards the first stop position thereof, causing the wheel of the pivoting lever to mesh with the motion work so as to set the time. When the stem is pulled out from the selection position, the intermediate lever and the moveable selector occupy a position which allows the pivoting lever to pivot towards the second stop position thereof under the action of the return spring, allowing the star-wheel to mesh with the date crown. However, this efficient device requires a large number of levers, and occupies space in an area which is already very overcrowded.
EP Patent No 0 230 878, in the name of COMPLICATIONS SA, offers moon phase correction using the intermediate position of the stem, between the winding and time-setting positions. In this position, the sliding pinion meshes with a lever that moves longitudinally in a hole, between a position that corresponds to a first direction of pivoting of the stem where it adjusts the date via a wheel carrying a star-wheel, and another position that corresponds to a second, opposite direction of pivoting of the stem, where it adjusts the moon phase, each time via a star-wheel. The moon phase disc is driven from an additional hour wheel, by a wheel including two elastic fingers, one of which cooperates with a star-wheel having seven teeth for the days of the week held by a jumper spring. The other finger cooperates with the toothing of the moon phase disc, which is also held by a jumper spring. These elastic fingers allow correction to be performed at any time without any damage, even if the fingers are meshed with the star-wheel.
Similarly, EP Patent No 0 479 147 in the name of ETA SA discloses a moon phase corrector using the control stem. It also includes a sliding pinion that can move in a hole in an arc of a circle, between positions for driving a date wheel or moon phase wheel, with which it cooperates via a top wheel, whereas a bottom wheel of this sliding pinion remains permanently meshed with a corrector wheel driven by the pivoting movement of the stem.
CH Patent No 651 172 in the name of WIEDERRECHT has a moon phase indicator with correction via the crown. A moon wheel with 59 teeth, held by a jumper spring, cooperates with a click, which is pivotally mounted off-centre, and can move between two flat stop sections, on an intermediate wheel whose pivot is carried by a flat spring and which meshes with a pinion driven onto the hour wheel. Once a day the click drives the moon disc, when an actuating tooth comprised in said click enters the toothing of the moon disc, and when a rear edge of the click abuts against a first flat section of the intermediate wheel, thus driving the moon wheel through one and a third teeth, so as to enable the jumper spring to jump one tooth. The lunar day is set by alternate forward and backward movements of the winding crown having an amplitude corresponding to one or two hours around midday. When the crown drives the hands in the anti-clockwise direction, the intermediate wheel pivots clockwise and, when the drive tooth of the click enters into contact with the front flank of a tooth of the moon disc, the click tips on the pivot thereof until it abuts a front edge on another flat section of the intermediate wheel. The drive tooth is then partially retracted, and, as the pivoting of the intermediate wheel continues, the moon disc is driven by one fifth of a tooth in the opposite direction, before the click escapes from the tooth of the moon disc which it was driving. The jumper spring then returns the moon disc to its former position, which means that the moon disc is driven step by step only clockwise towards the desired position. This ingenious device requires components of very small size, which are difficult to assemble and the device is quite fragile, in particular in the event of shocks.
Other types of mechanisms have been proposed for correcting the date or moon phases. Thus FR Patent No 2 862 143, in the name of MONTRES BREGUET SA, proposes the combination of a moon phase indicator having a date disc, with a ring having a double toothing. The date corrector is also used for correcting the moon phases. It has a pivoting lever, including a hole in which a star-wheel can move which, when it pivots clockwise drives the lunar wheel toothing, and when it pivots anti-clockwise remains at a distance therefrom owing to the hole.
EP Patent No 1 730 605, in the name of BLANCPAIN, presents a corrector device which is on or under horns, so as to free the crown and any other push buttons, and which includes a pivoting lever provided with a sealing gasket.
EP Patent No 1 939 699 A1, in the name of MONTRES BREGUET SA, discloses a multi-function coaxial corrector device for selecting or modifying display data by means of a single control member. A rotation of the control button causes a rack to move and the end of a lever arm to be positioned opposite a function corrector. Applications of pressure on the button activate and/or modify a selected function.
As an alternative to performing correction via the stem or push button, CH Patent No. 688 171, in the name of PATEK PHILIPPE, proposes performing correction by pivoting a moveable bezel, which carries two rotatably integral crowns, one engaging a toothed celestial wheel via a celestial disconnecting friction wheel, and the other engaging a toothed moon wheel via a moon disconnecting friction wheel, wherein both disconnecting wheels are friction mounted on a drive shaft provided with a wheel that meshes with a barrel. The toothed moon wheel includes an inner toothing cooperating with an off-centre moon phase wheel. A base plate includes two holes, in which the shafts of two intermediate celestial and moon disconnecting pinions can move. Depending upon the direction in which the moveable bezel is pivoting, these pinions can mesh one at a time with the corresponding disconnecting friction wheel. During correction, the disconnecting wheel concerned disconnects via friction on the drive shaft outside the correction phase, the corresponding intermediate disconnecting pinion is not meshed with the corresponding intermediate pinion. This construction offers an interesting alternative to known correction control means, but it requires special construction for the timepiece concerned, particular care as regards sealing, and involves high fabrication costs.
Other than correction mechanisms based on the use of the winding and time-setting stem, there exist few solutions for performing these corrections, except through the use of additional push buttons, which each time raise sealing problems and involve significant expense.
In particular, the equipment of timepieces such as chronographs requires further thought, to avoid increasing the number of control members, to guarantee sealing, in particular in deep sea diving conditions, and to keep the cost of the correction function at a reasonable level.